The effects of thyroid hormone and beta adrenergic agonists on target tissues may be evaluated by noninvasive monitoring of cardiovascular function. New techniques have been developed and evaluated for this purpose. The OKd interval, i.e. the interval between the onset of ventricular depolarization and the arrival of the pulse wave at the brachial artery, provides a rapid, innocuous, precise, reproducible noninvasive measurement for evaluation of thyroid, cardiovascular, or catecholamine status. This has been used for improved diagnosis and monitoring of therapy for patients with thyrotoxicosis, hypo-thyroidism, pheochromocytoma, and in the titration of effects of beta-adrenergic blockers such as propranolol. This method for noninvasive monitoring of cardiovascular patients has been applied in a prospective manner to evaluate patients receiving adriamycin chemotherapy, in an attempt to monitor cardiovascular toxicity. Preliminary results indicate a very high incidence of adriamycin cardiotoxicity and may make it possible to predict which patients develop overt congestive heart failure.